Trial results on two groundbreaking drugs are expected to bring new hope to patients with the deadliest form of skin cancer.
Together they mark the first significant step forward in treating advanced, spreading melanoma for more than 10 years, experts believe.
One of the drugs may be licensed for use in the UK within months.
Ipilimumab has just been approved in the United States as a "second line" back-up treatment for patients who have failed to respond to conventional chemotherapy.
New trial data shows that the drug, marketed as Yervoy by Bristol-Myers Squibb, also extends the lives of previously untreated patients.
They are due to be presented at the American Society of Clinical Oncology (Asco) meeting being held in Chicago in June.
Findings from a study demonstrating the effectiveness of another "cutting edge" new drug from Roche, PLX4032 - branded as Plexxicon - have also been submitted for presentation at Asco.
Currently the prospects for patients with spreading, or metastatic, melanoma are bleak.
Once the disease starts to spread from the skin to other parts of the body average life expectancy is only six to nine months.
Around 2,000 people are diagnosed with metastatic melanoma in the UK each year. The two new drugs offer the first real hope of extending their lives significantly, according to doctors.